GAZA CITY—A full-court diplomatic press is underway in the Middle East, with top U.S. and UN envoys scrambling to steer a week of intensifying Israeli-Palestinian violence back from the edge of ground warfare.

American Secretary of State Hillary Clinton will shuttle Wednesday to Cairo for extended truce talks after a day of rising expectations ended in abject failure and one of the highest body counts so far.

In a grisly twist, witnesses said Hamas militants added to the Palestinian death count as masked gunmen publicly executed six suspected collaborators at a crowded Gaza City intersection. All six were forced to lie face down and shot dead. The body of one was then tied to the back of a motorcycle and dragged through the streets, the Associated Press reported.

Throughout Tuesday, a ceasefire deal was said to be imminent, with Israel and Hamas poised to declare a midnight end to the mutual barrage of rockets and airstrikes to and from the Gaza Strip, the Islamic militant group’s coastal base.

But on the ground it was the storm before the calm — if calm is indeed to come — with volleys of long-range Palestinian rockets meeting more rounds of Israeli artillery bombardment and dozens of air strikes over Gaza by fighter jet and helicopter gunship.

More than 130 Palestinians have died, including at least 54 civilians, since hostilities erupted last Wednesday. And Tuesday, a non-military employee at an Israeli army base outside Gaza was killed by rocket fire, along with an 18-year-old soldier, bringing to five the number of Israeli casualties.

After arriving in Jerusalem late Tuesday, Clinton emerged from a meeting with Israeli Prime Minister Benjamin Netanyahu, cautioning that intense negotiations will continue with the goal of securing gains for both sides.

“In the days ahead the United States will work with our partners here in Israel and across the region toward an outcome that bolsters security for the people of Israel, improves conditions for the people of Gaza and moves toward a comprehensive peace for all people in the region,” she said.

Netanyahu signalled willingness to wait — but also offered a stark reminder that he is prepared to order the ground army now massed on Gaza’s borders to launch an incursion if diplomacy peters away.

“If there is a possibility of achieving a long-term solution to this problem with diplomatic means, we prefer that,” said Netanyahu.

“But if not, I’m sure you understand that Israel will have to take whatever action is necessary to defend its people.”

Egyptian President Mohammed Morsi, for a second day in a row, proved to be an overenthusiastic interlocutor, signalling again that a truce announcement was imminent.

But diplomatic sources briefed on the outlines for a deal suggested the momentum for ceasefire remains strong, with a tentative plan taking shape for an agreement structured in stages, beginning with a ceasefire of 24 to 48 hours to test Hamas on its ability to contain rocket fire from the various groups involved in the launch of projectiles from Gaza.

Clinton was expected to remain in the region to parlay an initial cessation of hostilities into a second-stage agreement aimed at securing longer-term stability with the carrot of easing elements of the Israeli blockade on Gaza.

Israel is said to be looking for international guarantees that Hamas will not use the easing of restrictions on Gaza to renew its arsenal. The more than 1,400 rockets fired at Israel over the past week have led to a wildly lopsided 25-to-1 body count, with far more Palestinians killed in some 1,500 Israeli air strikes.

Yet Israel’s determination to end the flow of rockets falling randomly has deepened now that the main cities of Tel Aviv and Jerusalem are within range for the first time. On Tuesday, air raid sirens sounded again in Jerusalem but the incoming rocket from Gaza fell in an open area southeast of the city.

Jerusalem remains an unlikely target because of the iconic gold-domed Al Aqsa Mosque, the third holiest site in Islam.

The overnight Israeli Defense Forces strikes on Gaza continued well into Wednesday, including some hits deep inside densely populated Gaza City. The targeted areas and casualty count were not immediately clear.

Earlier Tuesday, airstrikes continued as Turkey’s foreign minister and a delegation of his Arab League counterparts entered Gaza.

“Turkey is standing by you,” Turkish envoy Ahmet Davutoglu told Hamas Prime Minister Ismail Haniyeh in another sharp reminder of how far the once close Israel-Turkey ties have fallen. “Our demand is clear. Israel should end its aggression immediately and lift the inhumane blockade imposed on Gaza.”